Richter-like transformation of CLL/SLL after a temporary hold of ibrutinib: A case report

Abstract

Bruton tyrosine kinase (BTK) inhibitors are used to treat chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), providing survival benefits over traditional chemoimmunotherapy. Richter transformation is the transformation of CLL/SLL into an aggressive lymphoma, typically necessitating an immediate start of treatment. This case report presents a CLL/SLL patient developing pathology-proven Richter transformation after a short hold of the BTK inhibitor, without clinical evidence of disease progression. This case also demonstrates that the pathology-only Richter transformation after a pause of the BTK inhibitor can respond to resumption of the inhibitor, without the addition of intensive chemotherapy.